DR. DAVY'S ACCOUNT OF SOME EXPERIMENTS ON THE BLOOD. 299 



haustion of air from the lungs by the air-pump. A full-grown Guinea Pig was the sub- 

 ject of experiment in each. The one killed by strangulation died in about a minute 

 after a cord had been drawn tightly round its neck ; the other, placed on the plate of 

 the air-pump and confined by a receiver just large enough to hold it, lived about five 

 minutes after the exhaustion had been commenced, the pump the whole time having 

 been worked rapidly. The bodies were immediately examined. The heart of the 

 strangled animal was motionless; it was distended with dark blood; twelve mea- 

 sures of the blood, broken up and agitated with twenty-nine of carbonic acid gas, 

 absorbed eighteen measures, or 150 per cent. The heart of the other Guinea Pig was 

 also distended with blood, but of a less dark hue. Its auricles were feebly acting ; 

 the lungs were paler than in the former and more collapsed : ten measures of blood 

 from the heart, broken up and agitated with fifty of carbonic acid gas, absorbed thirty- 

 seven measures, or 370 per cent. ! 



Further, in illustration of this supposed secreting power of the lungs, I might ad- 

 duce the condition of the blood in disease, and in instances in which I have examined 

 it after death from disease, in the majority of which I have found the blood loaded 

 with carbonic acid, as indicated both by the disengagement of this gas, when the 

 blood was agitated with another gas, and by the comparatively small proportion of 

 carbonic acid which the blood was capable of absorbing. This condition of the blood, 

 in relation to carbonic acid, I believe to be one of great interest and importance, and 

 capable, when further investigated, of throwing light on many obscure parts of pa- 

 thology, and especially on the immediate cause of death, and that happy absence of 

 pain in dying which is commonly witnessed. 



As regards an exhaling power, which I suppose the lungs may possess, I conceive 

 it may be exercised occasionally under peculiar circumstances — circumstances, in the 

 first instance, favouring an accumulation of carbonic acid gas in the blood, as undue 

 pressure of any kind, and, in the second instance, circumstances of a different nature, 

 connected with the removal of undue pressure, admitting thereby the excess to pass 

 off. 



The view which I have alluded to relative to the production of animal heat, is, I 

 believe, capable of explaining very many particulars of animal temperature in differ- 

 ent classes of animals, and both during life, in health, and disease, and in a state of 

 hybernation and after death. If correct, this it must necessarily do, theory being 

 merely an expression of facts and truths in nature being perfectly consistent. 



Fort Pitt, Chatham, 

 May 30th, 1838. 



ERRATUM. 



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